Black PC must have changed its unusable now

Hello All,

I have this on a support ticket so hope I get an answer but curious if anyone using PC has seen these issues.

I run a production part only in black Bambu PC and have used over 20 spools and had the settings dialed and it never failed. I mean like never… I just ordered 8 spools at the black friday sale and added a 2nd x1C since I cant make the parts fast enough. Anyhow, now the material warps like mad. Lifts up from the build plate even if I use a Brim which I never ever needed prior. I am printing on a smooth PEI sheet and it always stuck and sometimes too well. Also I get an error on every print saying the following “Filament exposure metering failed because layer reflection is too weak on this material. First layer inspection may be inaccurate” I have never seen this error in over 20 spools of black PC until the material form this order. It happens every time on both my older machine and the one I just set up. Both are x1C. I think Bambu changed vendors or changed the formula on the PC and this is the byproduct of that change.

I am a bit screwed here now since the material is completely unusable to me and I bought the 2nd machine to be able to keep up with demand and now neither can print a good part. I may have to go back to Priline PC but its not pure PC which is why I used the bambu since it had a data sheet showing its strength and heat tolerance. My parts are exposed to high ambient heat and the bambu PC worked well.

Open at any advice and please help.

Presumably you done your own quality checks such as weighing a complete spool before and after drying, correct?

Also, have you done a bed leveling and a first layer test print? Preferably using the previous filament to compare against the new filament.

The first layer print test with bed leveling will provide a nice flat piece of filament that is only 1 layer thick. Hold the layer up next to the light to induce glare in order see how specular the surface is for both filament samples. Then hold it up directly in front of the light to see if you can see through the samples. If they are markedly different, go back to Bambu and ask for your money back.

Unfortunately I used the last of my previous material up already. All I have is white left from the older batch but don’t have a new white here to compare against. These are brand new out of the package and I have one in an AMS with very low humidity and the other in an active heating/drying box as I print. Same results on both. Also since both are popping off a reflectivity error then something must be different since it was an error I never saw before.

I am printing another part now with an enormous Brim to see if I can at the very least keep moving forward. I never had any warping issues with the Priline, but was afraid it was not pure PC and woudl not take the ambient heat. I may need to go back and then do a heat test this is many steps backward unfortunately since I though I was golden going with Bambu Material with existing testing data.

Well… sorry to hear about that. It sounds like your livelihood is relying in this and that must suck. The lesson though that you’ll take a way from this is not to trust any filament claims. I don’t and even when I repeat from the same source I always perform three quality tests out of the box.

  1. Temp Tower
  2. PA Pattern
    and if it does not pass those two then I run
  3. a max flow rate test.

After that I modify my filament profile to match the test.

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I wonder if you can do a work around for the reflectivity thing by changing the ambient light. Either more or less or a different angle? Try turning the internal light off. And maybe for giggles clean the camera lens. I know it’s not throwing an error for a dirty lens but maybe it’s right on the edge?

I assume you’ve done appropriate plate cleaning to eliminate any grease that could cause adhesion issues?

That’s actually a great idea. I should have mentioned that. For the times I have to perform optical work and glare becomes an issue, I simply tape some polarizing film over the camera lens if I don’t already have a camera with said lens.

The stuff can be had real cheap on Amazon. I’ve been using a packet of small sheets that’s lasted me years since one sheet can be cut into small pieces. I apply it to everything from Raspberry PI cameras to Webcams. It’s an extremely effective way of cutting glare off of anything and if one is doing any sort of image recognition AI as an example, this helps the AI algorithm a lot. There’s no reason why it wouldn’t benefit lidar or the X1 Cam for spaghetti detection.

I used to work in a CD replication facility. Birefringence was a big deal, we had a light box with a polarized light source that showed stress patterns in the disc. You could tell when the punch was getting worn well before you had issues with the disc cracking. This was a good thing to stay on top of when the 52X drives started coming out. Customers don’t like it when a disc explodes in a drive.


Yeah… I hate when that happened!!!


I am having the same issue with Bambu PC black. I did try different lighting, buildplates and also cleaned the lidar lens. No luck so far.
Any update in your case?

No help from Bambu on my end. Just some stupid try this message that was in no way pertinent to the issue I am having. Also no reply on the error whatsoever. I wish others using PC would verify they get the same error. So far your the only other person to corroborate what I am finding. Either the formula changed or something in the printer firmware that is causing the reflectivity error to happen. So in a sense I pretty much have a P1 printer when using PC since I am not getting accurate flow calibrations or lidar inspections…since these errors my PC prints have fallen considerable in quality as well as new odd issues like layer shifting. Worse yet I am pretty sure the formula changed since now I cant get a flat print to save my life. Even if I add a Brim. Before the issues, I never had any flat print issues, never needed a brim and quality was perfect. I just bought a 1.5mm thick G10 buildplate to help with the material shrinkage bowing the thin PEI buildplate. If it helps will let you know. Wont arrive for a few weeks.

I have only used Bambu’s “clear black” and it has problems with lidar for sure (but I can’t recall the exact messages). Not sure that’s a data point for you though, I take it you use opaque black?

Yes, the black (opaque) one.
Transparent or silk filaments may have issues with lidar but it seems that also dark filaments (some of them) may have the same issue. It is strange as I also use black PETG that is glossy and looks in general the same as this Bambu PC and the lidar works perfectly with it.
The error I am getting is something related to the exposure of the camera the lidar uses, like the filament is absorbing too much of the light the lasers are emitting.

I am not having any issues print quality wise, my X1C is printing PC like PETG. The only thing I’m doing is preheating the chamber setting the bed to 110C with the aux fan cycling the air until I get aroun 40C.
Also, as I could not auto calibrate flow… I’m not doing it manually neither (maybe I’m being lazy), so i’m using it as is.

I fixed my problem by switching to overture PC and it prints like the Bambu PC used to before. No warping and prints flawlessly. Unsure if its pure PC but will do some heat testing. However, seems Bambu customer service has gone from great to non existent. I have 2 tickets with not a single response from weeks ago.

It’s chinese new year and they are on holiday until Feb 18th I believe.

" Chinese New Year 2024 falls on Saturday, February 10th, 2024, and celebrations culminate with the Lantern Festival on February 24th, 2024."

They DO like to party!

Officially, only the first week is the New Year holiday, but apparently many companies take the full two weeks. I’m don’t know Bambu’s plans.

Overture pc is a blend. PC PETG. Then again Bambu PC is still a blend but 1% PETG. I can’t remember off hand but overture is a bit more.

Could be that they are using pure PC. If that’s the case great. Or just went to an even lower PETG blend.

You could use some vision miner nano polymer for better adhesion. Some PC blends like prline they put alot of PETG into it so if you put it on smooth pei with no prep it’s really hard to get it off.

More the. Likely it’s a blend issue. More or less PETG really impacts not only the properties of PC but how strong it’s bed adhesion is.

My tickets are all pre CNY by as much as a month.

I am not having the part lift off the bed. What is happening as it shrinks its adhesion is so great it bows the plate. Like the magnet is not strong enough to hold it. Anyone else having this issue? The Overture PC is doing better but has not fully fixed the issue. Also could be a geometry issue as well since my part is essentially a hollow rectangle with sides about 1" or more tall. Base is 7mm thick continuous. It is a functional item so no way to redesign it unfortunately. I have a G10 plat eon order that is 1.5mm thick and hope this helps with the bowing of the plate. Would higher heat on the bed help?

I used Priline before and liked it but was worried about too much PETG in the blend. I reached out to them and they never replied. This item needs to take high Ambient heat without warping when in use. Parts are here.